I saw it on Friday.
I really enjoyed it.
I am a HUGE fan of the book, and have been waiting fot this film for a long time. I wasn't disappointed, but I thought they could have done things differently.
For starters, they should have had more character development. I thought Arya's character was severely under-used, considering she is such a huge character in the book. Also, it never even explained what she is!
I thought the film should have been longer, say 2 hours at least, as then they could have developed the characters and slowed down the plot (Saphira growing fully should have been a longer process), giving them chance to explain things more.
As for the acting, I was quite happy with that. I think Ed Speelers was a very good choice for Eragon, and Jeremy Irons was quite good. Sienna Guillory was good for the few scenes she had, but I still think she should have had black hair, like in the book.
Saphira was my only actor (or voice) quibble - I didn't think the voice suited her that well. Maybe it's just me though.
Saying all that, I still really enjoyed it, and look forward to seeing it again!